Safety switch for oil burners



Jan. 27, 1931. c. L. RAYFIELD SAFETY SWITCH FOR OIL BURNERS Filed Aug. 10. 1927 2 Sheets-Sheet l c. L. RAYFlE-LD 1,790,246

Jan. 27, 1931.

SAFETY swITcH Fo'R oIL BURNERS Filed Aug. 10. 1927 2 Sheets-Sheet 2 x/E: ICI

Charles Rely/ald giu-"y2,

Patented Jan. 27, 1931 omiso STATES PATENT oFFicE CHARLES L. BAYFIELD, F CHICAGO, ILLINOIS SAFETY SWITCH FOR OIL BURNEBS Application led August 10, 1927. Serial No. 211,884.

This invention relates to a control for oil ed to be connected with the wires M of the burning systems and concerns itself with motor circuit through a relay armature or means for preventing the restarting of the switch 1. The wires L also connect with a motor until the furnace `has cooled ofi' and transformer 2. One of the induction coils on 6 means for stopping the motor if the fuel does one side of this transformer is electrically 55 not ignite Within a predetermined time. connected by means of a wire?) to a relay ycoil The invention comprises the novel st-ruc- 4 that is adapted when energizedfor attractture and combinations hereinafter described ing the armature 1 and closing the motor cirand more particularly pointed out and de.- cuit. The relay coil 4 is connected by means fined inthe appended claims, olf a conductor 5 with a secondary trans- 60 In the accompanying drawings which illusformer circuit 6 which in turn is connected trate a preferred embodiment of this invento a contact 7 of the furnace thermostatic tion and in which similar reference numerals Switch. The current from the contact 7 re- -refer to similar features in the different views, turns through a switch Vmember 8 to the sec- Figure 1 is a diagrammaticview illustrat- 0nd contact 9 of the furnace switch and from 65 ing the system in which this invention is inthere through a conductor l() to the boiler concorporated, the parts being shown in idle trol 11 and from the boiler control, the current positions, emerges througha conductor 12 to the room Figure 2 is an enlarged sectional view of a thermostat 13. From the. thermostat 13 the safety switch taken upon the line II--II of current passes through a conductor 14 to a 70 Figure 3, for stopping the motor if the fuel safety switch 15 which is normally closed but does not initially ignite within a predeterwhich may be opened by the coils 36 in the mined time. aforementioned secondary transformer cir- Figure 3 is an enlargedv plan view of the cuit 6 as will bey later more fully explained.

switch. p From the switch 15, the current returns 75 Figure 4 is an enlarged side view of the through a conductor 17 connected to a confurnace thermostat and switch. ductor block 18 from which the current Figure 5 is an enlarged end view of the emerges through a conductor y19 tothe other Yfurnace' thermostatic Switch, COil OI* Side Of the tIIiSfOI'IIleI. The Circuit Figure 6 is a Sectional ViewA npen the line just described is the starting circuit for the' VIK-VI of Figure 4. v system. It will. of course be understood that Figure 7 is a View of the safety switch t efurliace switch, the room thermostat and Shown in Figure 2, lboiler control are all closed when the system Figure 8 is an end view 0f the safety Switch, is idle or the parts are cooled to a suii'icient Figure 9 is a fragmentary part sectional degree view of the furnace thermostat and 4switch be running circuit of the system will now illustrating the frictional connection therebe dSCI`1b -i It Wlll be noted that a holding between. contact 20 is supported upon an arm extend- In'Figure 1 of the drawing, there is illusing from the Switch member 1. When the o trated in diagrammatic form a. Well known IDOtO Switch l. iS ClOSed, the holding Contact regulating Syst-,em in whiehthis invention was 20l is put' i-n contact with a. terminal 21 of incorporated. In order that this invention the running circuit 22 which leads to the and its relation in the system and its purpose boiler control 11 and from thence to the room may be readily understood, a. briefv descripthermostat 13. From the room thermostat, tion of the system with the invention incorpothe circuit traverses the conductors 14, 17, and rated therein as shown in Figure 1 will be 19, to one side of the transformer 2. This given. In referring to 4said .Figure 1, ythe running circuit is completed through the conwires L designate the volt line that supductor 3, relay 4, and kholding contact 20, lies/the current for the system.v The wires which isl connected through its arm to the lead to the motor. The wires L are adaptrelay coil.

rl`he structure of the safety switch and furnace switch will now be described. The safety switch is shown in'Tigures 2, 3, 7

and 8, and in referring to said figures, it will be noted that the switch comprises a support 23 having a switch member 24 of ...Z-shape, one flange of which is secured by a post 25 to the bottom of the supports 23. rEhe other flange forms a contact for one end of a switch member 26. TheV other end of this switch member is upwardly offset and this oilfset portion is attached to the support 23 by a post 2l'. Adjacent this oilset portion of said switch member, a bracket V28 is secured tothe switch member 26 and depends therefrom. The depending part of this bracket is provided with a central slot 29 (Figure and lateral notches 30 adjacent .said slot. Y Y

rheend of the support 23 opposite the bracket 28 is provided with depen ding block Y or portion 3l tothe bottom of which a thery mostatic element bar 32 is secured by a suitable screw 33. rllhe forward end of this thermostatic element is soffashioned as to provide a tongue 34 that entends through the slot 29 and lateral tines 35 that are located in the notches 30.k Suitable heating coils 36 extend lengthwise of the thermos-tatie bar 32. These coils are connected with the binding posts 37 on the support 23 by means of conductors`38.

e. cap plate 39 is securedupon a central boss 40 upon the top of thesupport 23. rlhis boss is provided with a socket 41 through which a plunger 42 passes that is adapted for engaging the switch member 26. A coil spring 43,. in said socket normally bears against a collar 44 on the plunger 42y for elevating the same above the switch member 26. The plunger maybe manually operated to move the switch member 26 to closed position.

The furnace thermostat which will now be described is illustrated in Figures 4, 5, 6, and 9. In referring to said figures, especially Figure 4, it will be noted lf have illustrated a furnace wall or door 45 to which a U-shaped thermostatic element 46 is attached by one Vof the branches or arms thereof. The other arm vnereof extends into a notch 47 in the underu side of a switch operated bar 48 which slidably entends through the furnace wall and through aswitch casing 49 attached in spaced relation to the furnace wall. rl`he outer end of the rod 48 is hollow as shown in Figure 9. A second rod 50 telescopes within the hollow portion of the rod 48 and is frictionally retained by a set screw 5l which is sustained in a 'small barrel or sleeve 52 attached to the' rod 48. This frictional connection providesl a certain amount of yield. The rod 50 slidably extends through the switch housing 49V has affixed upon its outer end a crosshead 54 which carries a pair of adjustable studs 55. The crosshead 54 is provided with a ing a guide stud or screw 57 extend ing from an insulated plate 58 that closes the adyacent side of the casing. Upon the face f t Vconnection with a contact post 62 extending 'through the plate 58. he switch members 59 lie under the studs 55 onV the crosshead 54 for movement thereby as will later more f ly appear.

is shown in Figure. 6, a pair of electrical conductors 63, are respectively connected to the posts 60 wiL1 ln the housing 49 and a pair ductors 64 are connected to of' electrical ccone post 62 whi e the other post 62 is connected bv conductor 65 with the diagonally `ppesite post 60. I

rifhe operation of this svstem will now be described. is soon as ythe current is turned on the relay 4 will attract the armature l and close the starting circuit which traverses the furnace switch which is closed when the furnace is cooled off. rit the same time the c current will also flow through theheatin coils 36 ofthe safety switch. Now if the fuel should not ignite and sta-rt the furnace to heat the sameV su'liicientlyv for actuating the thermostat -lfor moving the bar 48 for breaking the circuit through the furnace thermostatic switch in a predetermined time7 the coils 36 will have heated'the thermostatic bar 32 which will flex for actuating the switch member 26 for opening the switch and stopping the motor. n

However, if the fuel is properly ignited when the motor is started, the furnace will be sufliciently hea-ted te actuate the thermostatic bar 46 to move he bar 48 in a direction away from the furnace for opening the furnace thermostatic switch before the 'coils 36` open, the current through the safetyA switch is, of course, cut olf.

Obviously, when the vfurnace is function-k ing, the furnace thermostatic switch is open and it will be maintained in open position as long as the furnace is suliicientlyhot. New if the boiler or room thermostat should get in condition for opening" the running;

circuit of the motor, for stopping the motor 'the armature l would drop down byrgravity.

Then, before the system can start up again, it will be necessary for the furnace toV cool suciently to cause the thermostat 46 to actu. ate the bar 48 for closing the furnace thermostatic switch before the starting current can function again. Consequently, Aa safeguard, against starting-the system when the furnace is hot has been provided whereby,

explosions and the like are prevented in the furnace.

I am aware that numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted otherwise than necessitated by the prior art.

I claim as my invention:

l. In combination, a supporting wall, a switch supporting frame, a hollow bar slidable on said wall, a thermostat connected with said bar to control the slidin movement thereof, a rod slidable on sai frame and extending at its inner end into said hollow bar, switch mechanism on said frame controlled by the movement of said rod, and adjustable pressure means carried by said bar vand pressing said rod into frictional enf gagement with said bar whereby movement of said switch mechanism by said thermostat will be transmitted through the frictional connection of said bar and rod.

'2. In thermostatically controlled switch mechanism, the combination of an actuating bar structure comprising two members telescopically connected together for relative movement, a thermostat connected with the end of one of said members, switch controlling mechanism connected with the end of the other member, a barrel on one of said members having an adjustable spring pressed plunger therein engaging the other member whereby actuation of the switch mechanism by said thermostat will be through the resistance connection of said member.

In testimony whereof I have hereunto subscribed my name at Chicago, Cook county,

Illinois.

y CHARLES L. RAYFIELD. 

